New research from the Monell Center reveals that simply believing that an odor is potentially harmful can increase airway inflammation in asthmatics for at least 24 hours following exposure.

In the study, published online ahead of print in the Journal of Psychosomatic Research, 17 individuals characterized as moderate asthmatics were exposed for 15 minutes to the odor phenylethyl alcohol (PEA), which is regarded as a pure odorant with no associated physiological irritant qualities.

Individuals who were told the odor was potentially harmful rated it as more irritating and annoying as compared to those who thought it might be therapeutic. Also, airway inflammation increased immediately following odor exposure in subjects who believed the odor might be harmful and remained elevated 24 hours later. There was no increase of inflammation when the odor was characterized as therapeutic, even in individuals who described themselves as sensitive to perfumes and other odors.